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Brooks FJ, Gunsten SP, Vasireddi SK, Brody SL, Anastasio MA. Quantification of image texture in X-ray phase-contrast-enhanced projection images of in vivo mouse lungs observed at varied inflation pressures. Physiol Rep 2019; 7:e14208. [PMID: 31444862 PMCID: PMC6708057 DOI: 10.14814/phy2.14208] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/29/2019] [Revised: 07/25/2019] [Accepted: 07/27/2019] [Indexed: 12/13/2022] Open
Abstract
To date, there are very limited noninvasive, regional assays of in vivo lung microstructure near the alveolar level. It has been suggested that x-ray phase-contrast enhanced imaging reveals information about the air volume of the lung; however, the image texture information in these images remains underutilized. Projection images of in vivo mouse lungs were acquired via a tabletop, propagation-based, X-ray phase-contrast imaging system. Anesthetized mice were mechanically ventilated in an upright position. Consistent with previously published studies, a distinct image texture was observed uniquely within lung regions. Lung regions were automatically identified using supervised machine learning applied to summary measures of the image texture data. It was found that an unsupervised clustering within predefined lung regions colocates with expected differences in anatomy along the cranial-caudal axis in upright mice. It was also found that specifically selected inflation pressures-here, a purposeful surrogate of distinct states of mechanical expansion-can be predicted from the lung image texture alone, that the prediction model itself varies from apex to base and that prediction is accurate regardless of overlap with nonpulmonary structures such as the ribs, mediastinum, and heart. Cross-validation analysis indicated low inter-animal variation in the image texture classifications. Together, these results suggest that the image texture observed in a single X-ray phase-contrast-enhanced projection image could be used across a range of pressure states to study regional variations in regional lung function.
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Affiliation(s)
- Frank J Brooks
- Department of Bioengineering, University of Illinois at Urbana-Champaign, Urbana, Illinois
| | - Sean P Gunsten
- Department of Internal Medicine, Washington University School of Medicine, St. Louis, Missouri
| | - Sunil K Vasireddi
- Heart and Vascular Center, MetroHealth Campus at Case Western Reserve University, Cleveland, Ohio
| | - Steven L Brody
- Department of Internal Medicine, Washington University School of Medicine, St. Louis, Missouri
| | - Mark A Anastasio
- Department of Bioengineering, University of Illinois at Urbana-Champaign, Urbana, Illinois
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2
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Pinar IP, Jones HD. Novel imaging approaches for small animal models of lung disease (2017 Grover Conference series). Pulm Circ 2018; 8:2045894018762242. [PMID: 29480066 PMCID: PMC5888832 DOI: 10.1177/2045894018762242] [Citation(s) in RCA: 9] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Key Words] [Download PDF] [Figures] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 12/18/2022] Open
Abstract
Imaging in small animal models of lung disease is challenging, as existing technologies are limited either by resolution or by the terminal nature of the imaging approach. Here, we describe the current state of small animal lung imaging, the technological advances of laboratory-sourced phase contrast X-ray imaging, and the application of this novel technology and its attendant image analysis techniques to the in vivo imaging of the large airways and pulmonary vasculature in murine models of lung health and disease.
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Affiliation(s)
- Isaac P Pinar
- 1 Department of Mechanical and Aerospace Engineering, Monash University, Melbourne, VIC, Australia.,2 Division of Biological Engineering, Faculty of Engineering, Monash University, Melbourne, VIC, Australia
| | - Heather D Jones
- 3 Department of Biomedical Sciences, Cedars-Sinai Medical Center, Los Angeles, CA, USA
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3
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Rositi H, Frindel C, Wiart M, Langer M, Olivier C, Peyrin F, Rousseau D. Computer vision tools to optimize reconstruction parameters in x-ray in-line phase tomography. Phys Med Biol 2016; 59:7767-75. [PMID: 25419867 DOI: 10.1088/0031-9155/59/24/7767] [Citation(s) in RCA: 9] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/11/2022]
Abstract
In this article, a set of three computer vision tools, including scale invariant feature transform (SIFT), a measure of focus, and a measure based on tractography are demonstrated to be useful in replacing the eye of the expert in the optimization of the reconstruction parameters in x-ray in-line phase tomography. We demonstrate how these computer vision tools can be used to inject priors on the shape and scale of the object to be reconstructed. This is illustrated with the Paganin single intensity image phase retrieval algorithm in heterogeneous soft tissues of biomedical interest, where the selection of the reconstruction parameters was previously made from visual inspection or physical assumptions on the composition of the sample.
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Affiliation(s)
- H Rositi
- Université de Lyon, Laboratoire CREATIS, CNRS UMR5220, INSERM U1044, Université Lyon 1, INSA-Lyon, 69621 Villeurbanne, France
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Kitchen MJ, Buckley GA, Leong AFT, Carnibella RP, Fouras A, Wallace MJ, Hooper SB. X-ray specks: low dose in vivo imaging of lung structure and function. Phys Med Biol 2015; 60:7259-76. [PMID: 26348552 DOI: 10.1088/0031-9155/60/18/7259] [Citation(s) in RCA: 26] [Impact Index Per Article: 2.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/16/2022]
Abstract
Respiratory health is directly linked to the structural and mechanical properties of the airways of the lungs. For studying respiratory development and pathology, the ability to quantitatively measure airway dimensions and changes in their size during respiration is highly desirable. Real-time imaging of the terminal airways with sufficient contrast and resolution during respiration is currently not possible. Herein we reveal a simple method for measuring lung airway dimensions in small animals during respiration from a single propagation-based phase contrast x-ray image, thereby requiring minimal radiation. This modality renders the lungs visible as a speckled intensity pattern. In the near-field regime, the size of the speckles is directly correlated with that of the dominant length scale of the airways. We demonstrate that Fourier space quantification of the speckle texture can be used to statistically measure regional airway dimensions at the alveolar scale, with measurement precision finer than the spatial resolution of the imaging system. Using this technique we discovered striking differences in developmental maturity in the lungs of rabbit kittens at birth.
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Affiliation(s)
- Marcus J Kitchen
- School of Physics and Astronomy, Monash University, Clayton, Victoria, Australia
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5
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Dubsky S, Fouras A. Imaging regional lung function: a critical tool for developing inhaled antimicrobial therapies. Adv Drug Deliv Rev 2015; 85:100-9. [PMID: 25819486 DOI: 10.1016/j.addr.2015.03.010] [Citation(s) in RCA: 20] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/08/2014] [Revised: 03/18/2015] [Accepted: 03/20/2015] [Indexed: 12/11/2022]
Abstract
Alterations in regional lung function due to respiratory infection have a significant effect on the deposition of inhaled treatments. This has consequences for treatment effectiveness and hence recovery of lung function. In order to advance our understanding of respiratory infection and inhaled treatment delivery, we must develop imaging techniques that can provide regional functional measurements of the lung. In this review, we explore the role of functional imaging for the assessment of respiratory infection and development of inhaled treatments. We describe established and emerging functional lung imaging methods. The effect of infection on lung function is described, and the link between regional disease, function, and inhaled treatments is discussed. The potential for lung function imaging to provide unique insights into the functional consequences of infection, and its treatment, is also discussed.
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Affiliation(s)
- Stephen Dubsky
- Department of Mechanical & Aerospace Engineering, Monash University, Victoria 3800, Australia.
| | - Andreas Fouras
- Department of Mechanical & Aerospace Engineering, Monash University, Victoria 3800, Australia.
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6
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Guan H, Xu Q, Garson AB, Anastasio MA. Boundary-enhancement in propagation-based x-ray phase-contrast tomosynthesis improves depth position characterization. Phys Med Biol 2015; 60:N151-65. [PMID: 25831266 DOI: 10.1088/0031-9155/60/8/n151] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/12/2022]
Abstract
Propagation-based x-ray phase-contrast (PB XPC) tomosynthesis combines the concepts of tomosynthesis and XPC imaging to realize the advantages of both for biological imaging applications. Tomosynthesis permits reductions in acquisition times compared with full-view tomography, while XPC imaging provides the opportunity to resolve weakly absorbing structures. In this note, an investigation of the depth resolving properties of PB XPC tomosynthesis is conducted. The results demonstrate that in-plane structures display strong boundary-enhancement while out-of-plane structures do not. This effect can facilitate the identification of in-plane structures in PB XPC tomosynthesis that could normally not be distinguished from out-of-plane structures in absorption-based tomosynthesis.
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Affiliation(s)
- Huifeng Guan
- Department of Biomedical Engineering, Washington University in St. Louis, St. Louis, MO 63112, USA
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Leong AF, Buckley GA, Paganin DM, Hooper SB, Wallace MJ, Kitchen MJ. Real-time measurement of alveolar size and population using phase contrast x-ray imaging. BIOMEDICAL OPTICS EXPRESS 2014; 5:4024-38. [PMID: 25426328 PMCID: PMC4242036 DOI: 10.1364/boe.5.004024] [Citation(s) in RCA: 11] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 09/02/2014] [Revised: 10/16/2014] [Accepted: 10/18/2014] [Indexed: 05/09/2023]
Abstract
Herein a propagation-based phase contrast x-ray imaging technique for measuring particle size and number is presented. This is achieved with an algorithm that utilizes the Fourier space signature of the speckle pattern associated with the images of particles. We validate this algorithm using soda-lime glass particles, demonstrating its effectiveness on random and non-randomly packed particles. This technique is then applied to characterise lung alveoli, which are difficult to measure dynamically in vivo with current imaging modalities due to inadequate temporal resolution and/or depth of penetration and field-of-view. We obtain an important result in that our algorithm is able to measure changes in alveolar size on the micron scale during ventilation and shows the presence of alveolar recruitment/de-recruitment in newborn rabbit kittens. This technique will be useful for ventilation management and lung diagnostic procedures.
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Affiliation(s)
| | | | | | - Stuart B. Hooper
- The Ritchie Centre MIMR-PHI Institute of Medical Research and the Department of Obstetrics and Gynaecology, Monash University, Vic 3168,
Australia
| | - Megan J. Wallace
- The Ritchie Centre MIMR-PHI Institute of Medical Research and the Department of Obstetrics and Gynaecology, Monash University, Vic 3168,
Australia
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Leong AFT, Paganin DM, Hooper SB, Siew ML, Kitchen MJ. Measurement of absolute regional lung air volumes from near-field x-ray speckles. OPTICS EXPRESS 2013; 21:27905-23. [PMID: 24514306 DOI: 10.1364/oe.21.027905] [Citation(s) in RCA: 11] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/24/2023]
Abstract
Propagation-based phase contrast x-ray (PBX) imaging yields high contrast images of the lung where airways that overlap in projection coherently scatter the x-rays, giving rise to a speckled intensity due to interference effects. Our previous works have shown that total and regional changes in lung air volumes can be accurately measured from two-dimensional (2D) absorption or phase contrast images when the subject is immersed in a water-filled container. In this paper we demonstrate how the phase contrast speckle patterns can be used to directly measure absolute regional lung air volumes from 2D PBX images without the need for a water-filled container. We justify this technique analytically and via simulation using the transport-of-intensity equation and calibrate the technique using our existing methods for measuring lung air volume. Finally, we show the full capabilities of this technique for measuring regional differences in lung aeration.
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